{"id":30,"date":"2007-02-20T01:39:32","date_gmt":"2007-02-20T08:39:32","guid":{"rendered":"http:\/\/www.rahulnair.com\/blog\/2007\/02\/20\/the-tesla-roadster-the-perfect-elise\/"},"modified":"2009-07-22T15:59:54","modified_gmt":"2009-07-22T22:59:54","slug":"the-tesla-roadster-the-perfect-elise","status":"publish","type":"post","link":"http:\/\/www.rahulnair.net\/blog\/2007\/02\/20\/the-tesla-roadster-the-perfect-elise\/","title":{"rendered":"The Tesla Roadster – the perfect Elise?"},"content":{"rendered":"

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I had the opportunity to visit Tesla Motors<\/a> on a tour organized by SFF1<\/a> and would like to write up some of my thoughts about the company, its technology and their first car. This is going to be from the point of view of a petrol head engineer who daily drives an Elise \u00e2\u20ac\u201c take it how you will :-).<\/p>\n

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In case you haven\u00e2\u20ac\u2122t heard of Tesla, on account of the rock you have been living under for the last 6 months, it is a Bay Area automotive startup that is designing and building the Tesla Roadster<\/a> which will be the worlds first mass produced electric sports car. I have been especially interested in the Tesla since it based on the Lotus Elise<\/a> chassis and is in fact assembled by Lotus<\/a> in Hethel in an arrangement similar to that used on the Opel Speedster<\/a>\/Vauxhall VX200<\/a>. However unlike the Opel\/Vauxhall, which were more like badge engineered Elises, the Tesla uses a substantially modified Elise chassis with an all-electric powertrain and is a whole new beast. I had already had my first look<\/a> at the car during the Palo Alto British car meet<\/a> but this tour was a chance to actually look at the car internals and to talk to some of the people behind this revolutionary machine.<\/p>\n

The most important piece of new technology in the car is of course its electric powertrain. Unlike established car companies which are have a \u00e2\u20ac\u0153not invented here\u00e2\u20ac\u009d complex and prefer to develop their cars from scratch, Tesla followed a startup mentality and tried to source as much of the technology as they could. The most obvious example of this is in the way they created the battery pack for the car. Instead of trying to come up with new battery technology, they instead sourced the fastest growing battery technology available today \u00e2\u20ac\u201c the Lithium Ion batteries<\/a> used in notebook computers. They use 6831 off-the shelf Li-Ion cells to form a 50 kW battery pack that provide the power for everything on the car. For those of you who are worried about exploding batteries – Tesla uses a lot more battery management technology including a heating\/cooling system that keeps the batteries at their optimum operating temperature irrespective of the outside temperature.<\/p>\n

\"Lithium<\/a>\"Tesla<\/a><\/p>\n

The electric motor spins up to 13,500 rpm and produces 248 bhp and 200 ft\/lbs of torque while weighing just 125 lbs. The most startling thing about the torque is that you have maximum torque starting from 0 rpm all the way to 6000 rpm where it starts to slowly reduce. The entire powertrain has only 17 moving parts of which 15 are in the gearbox which is a clutchless 2 speed setup where 1st<\/sup> will take you to almost 70 while 2nd<\/sup> tops out at 130 mph. There is no reverse gear \u00e2\u20ac\u201c the motor (which has just 1 moving part, the rotor) just spins backwards when you want to reverse.<\/p>\n

Following the technology sourcing mindset further, Tesla sourced the entire chassis from Lotus. By doing this they not only got one of the best handling chassis in the world but they also gained instant credibility by partnering with a 7 time F1 world champion constructor. The bonded aluminium chassis is a modified version of the Elise chassis and the front half looks to be identical to that of the Elise. The side sills have been lowered 50 mm to enable (relatively) easy ingress\/egress which should make the Tesla more livable than the Elise. The rear subframe has been modified to hold the battery pack (900 lbs) and the motor (125 lbs) in the same position as the Elise engine to get similar handling characteristics. Following the Chapman philosophy of \u00e2\u20ac\u0153simplify and add lightness\u00e2\u20ac\u009d, Tesla has gone to great lengths to lower the weight and uses an all carbon fiber body to keep the weight down to 2500 lbs. The front suspension is identical to the base Elise except for the use of the AP Racing \u00e2\u20ac\u02dcbig brake\u00e2\u20ac\u2122 kit to handle the added weight of the Tesla.<\/p>\n

\"Tesla<\/a> <\/a><\/p>\n

The performance figures on the Tesla Roadster are pretty amazing:<\/p>\n